GREENHOUSE 



,mong amateurs. The housewife is always asking how 

 o make her wax-plant bloom, without knowing that it 

 rould bloom if she would let it alone in winter and let 

 : t grow in spring and summer. What we try to accom- 

 lish by means of fertilizers, forcing and other special 

 practices may often be accomplished almost without 

 ffort if we know the natural season of the plant. Nearly 

 ',11 Greenhouse plants are grown on this principle. We 

 : ;ive them conditions as nearly normal to them as pos- 

 ' ible. We endeavor to accommodate our conditions to 

 he plant, not our plant to the conditions. There are 

 ;ome plants which it is possible to make bloom in ab- 

 'iormal seasons, as roses, carnations, lilies : these we 

 ;aay force (see Forcing). But these forcing plants are 

 ew compared with the whole number of Greenhouse 

 .pecies. The season of normal activity is the key to the 

 Vhole problem of growing plants under glass ; yet many 

 'i young man has served an apprenticeship, or has taken 

 t course in an agricultural college, without learning this 

 >rinciple. 



The second principle from the plant side is this : The 

 greater part of the growth should be made before the 

 tlant is expected to bloom. It is natural for a plant first 

 o grow: then it blooms and makes its fruit. In the 

 jreat majority of cases, these two great functions do 

 lot proceed simultaneously, at least not to their full de- 

 rree. This principle is admirably illustrated in woody 

 ilants. The gardener always impresses upon the ap- 

 prentice the necessity of securing " well ripened wood " of 

 Vzaleas, Camellias, and the like, if he would have good 

 lowers. That is, the plant should have completed one 

 :ycle of its life before it begins another. From imma- 

 ure and sappy wood only poor bloom may be expected. 

 Phis is true to a large degree even in herbaceous plants. 

 The vegetative stage or cycle may be made shorter or 

 onger by smaller or larger pots, but the stage of >rat>id 

 growth must be well passed before the best bloom is 

 vanted. Fertilizer applied then will go to the pro- 

 luction of flowers ; but before that time it will go to 

 ;he production of leaf and wood. The stronger and bet* ; 

 ;er the plant in its vegetative stage, the more satisfac- 

 tory it will be in its blooming stage. 



Closely like to the last principle is the law that check- 

 ng growth, so long as the plant remains healthy, in- 

 luces fruitfulness or florifttrousnexs. If the gardener 

 continues to shift his plants into larger pots, he should 

 not expect the best results in bloom. He shifts from 

 pot to pot until the plant reaches the desired size; then 

 :ie allows the roots to be confined, and the plant is set 

 nto bloom Over-potting is a serious evil. When the 

 dooming habit is once begun, he may apply liquid ma- 

 aure or other fertilizer if the plant needs it. The rose- 

 grower or the cucumber-grower wants a shallow bench, 

 hat the plants may not run too much to vine. 



Most plants demand a particular season of inactivity 

 >/ rest. It is not rest in the sense of recuperation, but 

 it is the habit or custom of the plant. For ages, most 



GREENHOUSE 



695 



thick rhizomes always signify that the plant was obliged, 

 in its native haunts, to carry itself over an unpropitious 

 season, and that a rest is very necessary, if not abso- 

 lutely essential, under domestication. Instinctively, we 

 let bulbous plants rest. They usually rest in our winter 

 and bloom in our spring and summer, but some of them 

 of which some of 

 the Cape bulbs, as 

 Nerines, are exam- 

 ples rest in our 

 summer and bloom 

 in fall. 



each species ; but, 



1004. Rose house, 150 x 20 ft., piped for steam. 



The natural habitat of the plant is significant to the 

 cultivator: it gives a suggestion of the treatment under 

 which the plant will be likely to thrive. Unconsciously 

 the plant-grower strives to imitate what he conceives to 

 be the conditions, as to temperature, moisture and sun- 

 light, under which the species grows in the wild. 

 We have our tropical, temperate and cool houses. Yet, 

 it must be remembered that the mere geography of a 

 plant's native place does not always indicate what the 

 precise nature of that place is. The plant in question 

 ,may grow in some unusual site or exposure in its native 

 wills. In a general way, we expect that a plant com- 

 ing from the Amazon needs a hothouse; but the details 

 of altitude, exposure, moisture and sunlight must be 

 learned by experience. Again, it is to be said that plants 

 do not always grow where they would, but where they 

 must. Many plants which inhabit swamps thrive well 

 on dry lands. 



Tae upshot of all this is, that the habitat and the 

 zone give the hint : with this beginning, work out the 

 proper treatment. Examples are many in which culti- 

 vators have slavishly followed the suggestion given by 

 a plant's nativity, only to meet with partial failure. Be- 

 cause the Dipladenia is Brazilian, it is generally sup- 

 posed that it needs a hothouse, but it gives best results 

 in a coolhouse. Persons often make a similar mistake 

 in growing the pepino warm, because it is Central and 

 South American. Ixia is generally regarded in the 

 North as only a glasshouse subject because it is a Cape 

 bulb, yet it thrives in the open in parts of New England, 

 when well covered during winter. 



The best method of propagation is to be determined for 



1003. Violet house with water heating. 



plants have been forced to cease their activities because 

 ;of cold or dry. These habits are so fixed that the plants 

 must be humored when they are grown under glass. 

 Some plants have no such definite seasons, and will grow 

 more or less continuously, but these are the exceptions. 

 Others may rest at almost any time of the year; but most 

 plants have a definite season, and this season must be 

 learned. In general, experience is the only guide as to 

 whether a plant needs rest; but bulbs and tubers and 



as a rule, quicker results and 

 stockier plants are obtained from 

 cuttings than from seeds. Of neces- 

 sity, most Greenhouse plants are 

 grown from cuttings. In the great 

 majority of cases, the best material 

 for cuttings is the nearly ripe wood. 

 In woody plants, as Camellias and 

 others, the cutting matedal often 

 may be completely woody. In 

 herbaceous plants, the proper ma- 

 terial is stems which have begun 

 to harden. Now and then better 



results are secured from seeds, even with perennials, 

 as in Grevillea and Impatiens Sultani. 



Coming, now, to some of the principles which underlie 

 the proper management of the house, it may be said, 

 first of all, that the grower should attempt to imitate a, 

 natural day. There should be the full complement of 

 continuous sunlight ; there should be periodicity in 

 temperature. From the lowest temperature before 

 dawn, there should be a gradual rise to midday or later. 



